Woodworking machine blade guard



Jan. 2, 1951 w, cQP

WOODWORKING MACHINE BLADE GUARD 2 Sheets-Sheet 1 Filed Oct. 16, 1948 INVENTOR WILL/AN COP}? 2 Sheets-Sheet 2 Filed Oct. 16, 1948 I HIE] /NVENTOR NIL/19M COPP M flTT'X Patented Jan. 2, 1951 WOODWORKING MACHINE'BLADE GUARD William Copp, Guelph, Ontario, Canada,.assignor to. Callander. Foundry & Manufacturing 00., Limited, Guelph, Ontario. Canada, a corporation of Canada Application October 16, 1948, Serial'No. 54',910

3 Claims.

This invention relates to woodworking tools, and is particularly concerned with improvements in blade guards for jointers.

Since jointers are, by their very nature, provided with a cutter head having blades which revolve at a high speed, it. is necessary from a standpoint of safety, and it isin some localities required by law, that the cutter head be normally covered by a guard. When a piece of lumber is being worked on the machine, the guard must be displaced by the piece of lumber; the better types of jointers include a swingable guard. which is urged by a spring into blade-guarding position, and the configuration of these guards is usually such that piece of lumber pushed against it as it is about to be fed towards the cutter head will provide a camming action on the guard and move it away from the blades. However, the guard is constantly urged into blade-guarding position,

and therefore the rotating blades are normally covered either by the guard itself or else partially by the piece of lumber which is being worked and partially by the guard.

A typical prior art construction jointer blade guard is disclosed in Figs. 1 and 2 of T. L. Hedgpeths U. S. Patent No. 2,099,519, dated November 16, 1937. It is frequently necessary for certain woodworking operations, particularly rabbeting, to remove the guard, but with prior art constructions this could'not be done conveniently and easily. Thus, for example, in the Hedgpeth construction referred to above it is necessary to first disconnect and remove a helical spring [11; this of course is not a convenient procedure, and occasionally the spring is lost to the considerable annoyance of the operator.

It is the main object of this invention to provide a blade guard having a mounting whereby it is normally urged to blade guarding position, but the said mounting being constructed so that the blade guard can easily be removed from the machine by simply pulling the guard upwardly, without disconnecting any small parts, and also so that the blade guard may easily be reassembled on the machine.

The foregoing and still further objects and advantages of the invention willbecome; apparent from a study of the following specification, taken in conjunction with the accompanying drawings, wherein like characters of reference designate corresponding parts throughout. the several views, in which:

Fig. .1 is 'a front perspective view of a jointer which "is adapted to be inserted in the opening having a. blade guard constructed in accordance with this invention;

Fig. 2 is av fragmentary vertical sectional View taken onthe plane of the line 2--2 of Fig. 1, looking in the direction of the arrows;

Fig. 3 is a horizontal section line 3-3 of Fig. 2, looking in the direction of the arrows; and

Fig; 4 .is a fragmentary vertical cross-sectional view of the blade'guard mounting.

Referring to the: drawings, I'll designates a jointer base having bearings in which is. journ-alled a cutter head H driven in any suitable manner; A front table :2 and a rear.' table 18 are slid-ably mounted on the usual inclined ways it and t5 formed on the base It, so as to be capable of raising and; lowering with respect to the cutter head. The tables are independently movable by means of any suitable adjusting means, here shown to include adjusting knobs It and I1. The front table I2 is formed at one side with a rabbeting arm or ledge t8, and the "rear table I3 is formed at the same side with a grooved edge I9 to provide clearance for rabbeted work. At the rear side of the tables is a fence 20 mounted in any suitable manne so that both its transverse position and its inclination may bevaried.

As may be seen particularly in Figs. 2 and 3the jointer base iliis a hollow casting. and there is provided integrally therein an open ended socket member 2! which provides a bearing having one end opening at the interior of the base and its other end opening at the exterior of the base.

In the bearing is rotatably mounted a hollow cylinder or sleeve '22 which has in its periphery tvvo annular grooves 23 and 24. A pin '25 extends transversely in the socket member and engages the peripheral groove 23 in the cylinder 22 whereby the cylinder can be rotated in its bearing but cannot be displaced axially with respect thereto.

A tension spring 26 is connected at one end by means of a screw 21 to the cylinder 22 at the peripheral groove 24, and the other end of the said spring is suitably connected at lug 28' to the base member In. As may be seen particularly in Fig. 3, spring 26 gives the cylinder '22 a turning moment in one direction.

Extending diametrically across the cylinder 22 and opposite peripheral groovej23, is a keying pin 25. An upstanding guard supporting rod 30 of cylinder 22 has at itslower end .a longitudinal slot 3! which'is adapted to engage the keying pin 29, Thus the keying pin and the recess 3| in the supporting rod 30 provide a connection between the cylinder and the rod whereby the said cylinder and rod can be displaced axially but cannot be rotated with respect to each other.

One end 29a of the keying pin 29 projects beyond the bottom of groove 23 and is flush with the outer periphery of cylinder 22, whereas the other end of the keying pin is flush with the bottom of the groove 23. Thus end 29a of pin 29 provides a stop which will engage pin 25 when the guard is at maximum blade guarding position, and prevent further rotation of the cylinder 22 and of supporting rod 30 connected therein despite the turning moment of spring 26.

The swingable guard 32 comprises a cast metal member of sufficient length and width so that its main body covers the cutter I I and the opening therefor which exists between the table sec tions l2 and I3. The guard is provided with an extending arm 33 to which the supporting r 3!] is suitably secured.

Sprin urges the guard 32 into the blade guarding position of Fig. 1, from which it may be moved by hand or by any work piece which engages the work engaging edge 34 of the guard. The angle or" this work engaging edge is such,

with respect to the direction of passage of work longitudinally of the tables, that a piece of lumber engaging the said edge cams the guard laterally with respect to the top of the table. As soon as the work has passed, the guard moves .back into the position of Fig. 1, covering the out- 1 ter and preventing possible injury to the opera- .tor.

' If it should be necessary to remove the guard, say for rabbeting, the operator merely has to grasp the guard supporting rod and lift it upwardly whereby it may be withdrawn from the cylinder 22. To reassemble the guard in the machine the operator merely inserts the lower end of-the guard supporting rod 30 in the cylinder 22 and forces the rod downwardly until the slot or reces 3| engages the keying pin 29. It is clear from the above description that removal of the guard from the machine does not entail the disconnection of spring 2% or of any small parts, since the cylinder 22 and the various other parts whereby it is connected to the body of the machine at all times remain a permanent part of the machine. Moreover the spring 26 is hidden inside the machine and therefore it cannot be damaged by an accidental blow.

The engagement of end 29a of keying pin 29 with pin 25 at a predetermined position of cylinder Z2 prevents total loss of tension in spring 26 in the event that the fence 28 is moved back abnormally, or in the event that the guard supporting rod 38 is withdrawn from the cylinder 22. Moreover, this feature enables the operator to reassemble the guard in the machine Without dimculty since he knows at What position slot ,3! in rod 36 will invariably engage keying pin 29 .and he does not have to depend on trial and error methods.

It is thought that the construction and use of the invention will be apparent from the above description of the various parts and their purpose. It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of thesame and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope ol' the subjoined claims. I I

. What I claim as my invention is:

,1. In a ma'chine'tool, a swingable. blade guard, V

an upstanding rod on which the guard is mounted, a rod supporting cylinder, a connection between the cylinder and the rod whereby said cylinder and rod can be displaced axially but not rotated with respect to each other, a socket member having a bearing in which the cylinder is rotatably mounted, a peripheral groove in the cylinder, a pin extending transversely in the socket member and engaging the peripheral groove in the cylinder whereby the cylinder can be rotated in the bearing but icannot be displaced axially with respect thereto, a stop in the said peripheral groove adapted to engage the pin When the cylinder is rotated to a predetermined position to prevent rotation of the cylinder beyond the said position.

2. In a machine tool, a swingable blade guard, an upstanding rod at the upper end of which the guard is mounted, a rod supporting cylinder, an opening at one end of the cylinder in which the lower end of the rod is adapted to be inserted, a keying pin transversely mounted in the cylinder and extending into the opening, a cut-away portion at the lower end of the rod adapted to engage with the pin so that the rod and cylinder cannot rotate with respect to each other, a socket member having a bearing in which the cylinder is rotatably mounted, a peripheral groove in the cylinder, a pin extending transversely in the socket member and engaging the peripheral groove in the cylinder whereby the cylinder can be rotated in the bearing but cannot be displaced axially with respect thereto, one end of the keying pin extending into the said peripheral groove and providing a stop to engage the pin when the cylinder is rotated to a predetermined position to prevent rotation of the cylinder beyond the said position.

3. In a machine tool, a hollow base member having a vertically disposed open ended socket opening at its lower end into the interior of the base member and opening at its other end to the exterior of the base member, a, swingable blade guard, an upstanding rod On which the guard is i mounted, a rod supporting cylinder rotatably mounted in the socket and having its lower end extending below the lower end of'the socket to project into the interior of the base member, a connection between the Icylinder and the rod of the kind which permits axial displacement of the rod relative to the cylinder but does not permit relative rotation thereof, and a spring connected between the interior of the base member and the end of the cylinder which projects into the in terior of the base member, the said spring giving the cylinder a turning moment in one directicn to urge the guard into blade guarding position.

WILLIAM COPP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 202,312 Warner Apr. 9, 1878 767,545 Davidsen Aug. 16, 1904 1,508,685 Flohr Sept. 16,1924 2,099,515) Hedgpeth Nov. 16., 1937 FOREIGN PATENTS Number Country Date 

